Pressing device for the removal of water from cellulose or the like

ABSTRACT

This invention relates to an improvement in a pressing device for the removal of water from solid materials, particularly cellulose or similar fibrous material, comprising a preliminary pressing station and a main pressing station including pairs of upper and lower horizontal rollers between which a sheet or web of material to be dehydrated is passed, on a sieve or between two sieves. The improvement comprises a lower roller mounted ahead of the paired upper rollers in a staggered manner in the traveling direction of the sieve, in at least one of said preliminary and main pressing stations.

United States Patent Heissenberger [45] F b, 19, 1974 [54] PRESSINGDEVICE FOR THE REMOVAL 714,679 12/1902 Ebcrly 100/153 X OF WATER FROMCELLULOSE OR THE 1,483,562 2/1924 Wagner. 162/358 LIKE 2,783,689 3/1957Sko1dkv1st 162/358 X 3,274,924 9/1966 Walker 100/153 51 t:OttH'b ,At' [71 or Us FOREIGN PATENTS OR APPLICATIONS 1731 Assign: MaschinenfabrikAndria 614 111 12/1960 Italy 100 113 Actiengesellschaft, Graz Andritz,Austria Primary Examiner-Peter Feldman [22] Filed: Mar. 27, 1972Attorney, Agent, or Firm-James E. Bryan, Esq. [21] Appl. No.: 238,450

[57] ABSTRACT Foreign Application Pri it D t This invention relates toan improvement in a pressing Apr. 5 1971 Austria 2890/71 device for theremoval of water from nd materials particularly cellulose or similarfibrous material, com- 52 US. on /118, 100/154, 162/358 prising aPreliminary Pressing Swim and a mm 51 Int. (:1 B30b 9/24, B30b 5/04Pressing Station including Pairs PP' and lower 58 Field of Search100/151-154 horizontal rollers between which a Sheet Web Of 119 materialto be dehydrated is passed, on a sieve 01' be- 314 5 3, 5 5 51 144/581tween two sieves. The improvement comprises a lower roller mounted aheadof the paired upper rollers in a [56] References Cited staggered mannerin the traveling direction of the UNITED STATES PATENTS sieve, in atleast one of said preliminary and main pressing stations. 403,744 5/1889Flood 162/314 502,523 8/1893 Lockstaedt 100/151 9 Claims, 2 DrawingFigures 1 D l a \\v 15 I |6 |4 2 l1 4 I l 1 8 2 K 17 1 '1 "L, 9 1' 1 l 2l j 2 3 W] M] g H I $1; I! I 1/ 1 I g "l 0 1- 1 L, a I

PAIENTED EB 1 Sam 1 0r 2 PRE S SING DEVICE FOR THE REMOVALOF WATER FROMCELLULOSE OR THE LIKE large extent is further dehydrated between pairsof rollers in a preliminary squeezing station and in a main pressing orsqueezing station. This involves or results in the disadvantage,however, that the squeezed-out water again reaches or arrives on thesheet or web and is suctioned into the material so that the dehydratingeffect is impaired.

The present invention has the object of counteracting this disadvantage.In the preliminary squeezing station and/or in the main pressing orsqueezing station, the lower roller of one pair of rollers is arrangedor offset ahead, compared with or with respect to the upperrollerthereof in the direction of travel of the sieve. By virtue of thefact that the lower roller is mounted ahead with respect to the upperroller, the sieve, and therewith the sheet or web of material to bedehydrated, is tightened against the upper roller ahead of the point ofapplication of the lower roller so that the sheet or web, beforeentering into the roller gap, is pressed against the upper roller at aspecific looping angle. Above this looping angle, the sheet or web ofmaterial is positioned under pressure so that a suctioning in of themoisture, which is being squeezed out at the underside of the sheet orweb by the lower roller, is effectively counteracted.

As a result thereof, entry of the liquid into the sheet or web at theunderside is largely prevented. Ahead of the upper roller, however, thesheet is not pressed so that at the upper side of the sheet or web thewater being retained by the upper roller will again reach the sheet,involving the danger that this water will penetrate from above into thesheet. By reason of the fact that the upper roller is set back ascompared with and with respect to the lower roller and the sheet or webof material is pressed against the upper roller only by means of thesieve, and will be squeezed out only later in the roller gap between theupper roller and the lower roller, the danger of a penetration into thesheet of water being pushed back by the upper roller is increased, suchthat part of the improvement of the drainage or dehydration which hasbeen achieved by the forwardly-shifted setting or arrangement of thelower roller is again canceled out. This phenomenon may be counteracted,in accordance with the present invention, in that, in the preliminarypressing or squeezing station and/or in the main pressing or squeezingstation, the sheet of material is guided in an ascending fashion, andtransverse channels are disposed in front of the upper rollers, whosefront edges touch the sheet of material or the upper sieve. The frontedges of the transverse channels preferably extend into the catchmentgap of the upper rollers. In this manner, the water which is preferablydischarged at the upper side of the sheet, due to the resetting orbackwardly-shifted arrangement of the upper rollers, is carried offlaterally, and moistening of the sheet with this water is effectivelyprevented.

The forward setting or arrangement of the lower rollers may be soselected, for example, that the resulting looping angle of the upperroller in the preliminary pressing or squeezing station amounts to 5 20,preferably approximately I0", and in the main pressing or squeezingstation 10 45, preferably approximately 30.

By virtue of the present invention, the dehydrating efiect is thussignificantly improved. The present invention is primarily suitable forthe removal of water from cellulose or similar fibrous material; but italso may be employed for the removal of water from non-fibroussubstances, such as for example mud, or foodstuffs.

One embodiment of the present invention is schematically illustrated inthe accompanying drawing, wherein FIG. 1 is a view of a cellulosedehydrating machine, and

FIG. 2 illustrates the preliminary pressing or squeezing station and themain pressing or squeezing station at an enlarged scale.

The fibrous material to be dehydrated is conveyed or fed between twoendless sieves, namely the lower sieve l and the upper sieve 2, to thecellulose dehydrating machine. Reference numeral 3 designates the sheetor web of material to be dehydrated or freed from water. The sheet ofmaterial 3 passes first through the wet portion or station A in whichthe water is suctioned off, and then travels into or reaches theregistering portion or station B in which a first squeezing-out of themoisture is effected between pairs of rollers. Thereupon, the materialpasses into the preliminary pressing or squeezing station C where afurther squeezing-out of the water takes place between pairs of rollers.In the adjacent main pressing or squeezing station D, the liquid issqueezed out between two rollers, with a great amount of pressure, up toan admissible residual part.

FIG. 2 illustrates the preliminary pressing or squeezing station C andthe main pressing or squeezing station D at an enlarged scale. The sheetor web of material 3 positioned between the lower sieve l and the uppersieve 2 is passed through between the pairs of rollers 6, 7 in thepreliminary pressing or squeezing station C. The lower roller has beenidentified therein with reference numeral 6 while the upper roller hasbeen identified with reference numeral 7. The lower rollers 6 aremounted ahead or forwardly offset as compared with and with respect tothe coordinated upper rollers 7 in the traveling direction of the sieve,as indicated by the arrow 8. The material rests against the upper roller7 within the area between the roller gap 9 and the running-up point 10,which will result in a looping angle or around the upper roller. Thislooping angle a is between 5 and 20, depending upon the extent of theforwardly shifted or staggered arrangement of the lower roller, andpreferably may amount to approximately 10. As a result, the sheet or webof material 3 is pressed against the upper roller by means of the lowersieve 1 within the looping area or zone defined by the looping angle a,and by virtue of this pressing, a penetration into the sheet or web ofthe water being dammed up by the lower roller in the roller gap 9 isprevented to a large extent.

The water is dammed up or held back at the runningup point 10 of thematerial sheet or web also by the upper roller. In order to prevent asmuch as possible a penetration there of the dammed up water into thesheet of material 3 from above, transverse channels 11 are provided forwhose front edges 12 touch the sheet of material 3 and/or the uppersieve 2, if the latter is employed. As a result, the water being heldback or dammed up on the upper side of the sheet of material 3, andrespectively the upper sieve 2, is laterally carried off, and apenetration thereof into the sheet of material 3 is thus prevented. Inorder to catch this dammed-up water as closely as possible to the pointof engagement of the upper roller, the front edges 12 of the transversechannels 11 extend into the catchment gap 13 of the upper rollers, asindicated in the drawings.

Also in the main pressing or squeezing station D is the lower mainsqueezing or pressing roller 14 mounted ahead or pre-set as compared tothe upper main pressing or squeezing roller 15 in the travelingdirection 8 of the sheet of material 3. In this case, the roller gapbetween the lower roller 14 and the upper roller 15 has been designatedwith reference numeral 16 whereas the running-up point of the uppersieve 2 and, respectively, the sheet of material 3 on the upper rollerhas been identified with reference numeral 17. Between the points 16 and17, there will be produced a looping angle [3 of the upper sieve 2 and,respectively, the sheet of material 3 around the upper roller. Thislooping angle B may be from to 45 and preferably is approximately 30.The effect is again the same as has been described hereinbefore inconnection with the pairs of rollers of the preliminary pressing orsqueezing station C. In the area or zone of the looping angle B, thesheet of material 3 is pressed against the upper roller by means of thelower sieve 1, whereby a penetration of the liquid being dammed up orheld back by the lower roller 14 is effectively counteracted. Hereagain, a transverse channel 18 is provided whose front edge 19 touchesthe upper sieve 2 and the sheet of material 3 so that the water beingheld back or dammed up by the upper main roller 15 is laterally carriedoff.

It will be obvious to those skilled in the art that many modificationsmay be made within the scope of the present invention without departingfrom the spirit thereof, and the invention includes all suchmodifications.

I claim:

1. A press for dehydrating materials, particularly cellulose or likefibrous materials, including a preliminary pressing station and a mainpressing station in which the material to be dehydrated is passedthrough a sieve or between two sieves and between at least two pairs ofhorizontally-disposed rollers defining at least one of said preliminarypressing station and said main pressing station and each consisting ofan upper roller and a lower roller, the improvement comprising eachsuccessive pair of said pairs of rollers, with respect to the directionof the path of travel of said material to be dehydrated, being disposedat a height greater than the height of the next previous pair of saidpairs of rollers in a manner to form a gradually ascending path oftravel of said material to be dehydrated which forms an acute angle witha horizontal plane and said lower roller of each of said pairs ofrollers being offset from andforward of said upper roller of said pairof rollers, with respect to said direction of travel of said material tobe dehydrated, to form an acute angle a between a line through thecenter of said upper roller and perpendicular to said material to bedehydrated and a line through said center of said upper roller and thecenter of said lower roller, whereby said material to be dehydratedforms an arcuate loop over the bottom of said upper roller between theside limits of said angle a.

2. A press in accordance with claim 1 wherein at least one of said pairsof rollers ispart of the main pressing station and a line through thecenter of the upper roller of said pair of rollers in said main pressingstation and perpendicular to the material to be dehydrated and a linethrough said center of said upper roller and the center of the lowerroller of said pair of rollers in said main pressing station form anangle B which is larger than the angle a of the remaining ones of saidpairs of rollers.

3. A press in accordance with claim 2 wherein the angle B is between 10and 45.

4. A press in accordance with claim 3 wherein the angle ,8 is about 30.

5. A press in accordance with claim 2 wherein the rollers in the mainpressing station are larger in diameter than the rollers in thepreliminary pressing station.

6. A press in accordance with claim 1 wherein the angle a is between 5and 30.

7. A press in accordance with claim 6 wherein the angle a is about 10.

8. A press in accordance with claim 1 wherein trough means are disposedbehind the upper rollers of the pairs of rollers, with respect to thedirection of travel of the material to be dehydrated, and the frontedges of said trough means are in contact with one of said material tobe dehydrated and an upper sieve of the two sieves.

9. A press in accordance with claim 1 wherein all of the pairs ofrollers are a part of the preliminary pressing stationv

1. A press for dehydrating materials, particularly cellulose or likefibrous materials, including a preliminary pressing station and a mainpressing station in which the material to be dehydrated is passedthrough a sieve or between two sieves and between at least two pairs ofhorizontally-disposed rollers defining at least one of said preliminarypressing station and said main pressing station and each consisting ofan upper roller and a lower roller, the improvement comprising eachsuccessive pair of said pairs of rollers, with respect to the directionof the path of travel of said material to be dehydrated, being disposedat a height greater than the height of the next previous pair of saidpairs of rollers in a manner to form a gradually ascending path oftravel of said material to be dehydrated which forms an acute angle witha horizontal plane and said lower roller of each of said pairs ofrollers being offset from and forward of said upper roller of said pairof rollers, with respect to said direction of travel of said material tobe dehydrated, to form an acute angle Alpha between a line through thecenter of said upper roller and perpendicular to said material to bedehydrated and a line through said center of said upper roller and thecenter of said lower roller, whereby said material to be dehydratedforms an arcuate loop over the bottom of said upper roller between theside limits of said anglE Alpha .
 2. A press in accordance with claim 1wherein at least one of said pairs of rollers is part of the mainpressing station and a line through the center of the upper roller ofsaid pair of rollers in said main pressing station and perpendicular tothe material to be dehydrated and a line through said center of saidupper roller and the center of the lower roller of said pair of rollersin said main pressing station form an angle Beta which is larger thanthe angle Alpha of the remaining ones of said pairs of rollers.
 3. Apress in accordance with claim 2 wherein the angle Beta is between 10*and 45*.
 4. A press in accordance with claim 3 wherein the angle Beta isabout 30*.
 5. A press in accordance with claim 2 wherein the rollers inthe main pressing station are larger in diameter than the rollers in thepreliminary pressing station.
 6. A press in accordance with claim 1wherein the angle Alpha is between 5* and 30*.
 7. A press in accordancewith claim 6 wherein the angle Alpha is about 10*.
 8. A press inaccordance with claim 1 wherein trough means are disposed behind theupper rollers of the pairs of rollers, with respect to the direction oftravel of the material to be dehydrated, and the front edges of saidtrough means are in contact with one of said material to be dehydratedand an upper sieve of the two sieves.
 9. A press in accordance withclaim 1 wherein all of the pairs of rollers are a part of thepreliminary pressing station.